1. Field of the Invention
This invention generally relates to a digital image signal processing system and method, and, in particular, to an image processing system using multiple image sensors for optically reading an original. More specifically, the present invention relates to an image processing system suitable for use in digital copiers, facsimiles, CAD apparatuses and filing input devices.
2. Description of the Prior Art
An optical image reading system using multiple image sensors is well known. In such an optical image reading system, multiple image sensors are operated at the same time to read segments of one scanning line simultaneously and the segmented image data are arranged in a line. With such a system, even if an original to be read is relatively large, in particular wide, in size, the original can be read at a high speed. However, since the segmented image data are integrated into one line within one scanning period, the integrated data must be processed at an increased speed. Thus, as the number of image sensors increase so as to accommodate a larger-sized original, the required processing speed for processing an integrated image data becomes higher. As a result, a high speed processor is required, which pushes up a cost. It is true that the image data for one line may be divided into two lines, i.e., even-numbered image data and odd-numbered image data, and these divided data may be processed in parallel at a reduced image processing rate. However, in this case, the image data obtained by a plurality of image sensors must be once integrated into a single line and then the image must be divided into a plurality of lines, so that the process tends to be complicated.
In particular, in an image processing system of this type, a magnifying processing in a size enlargement mode is carried out by either of (1) image data simple addition method and (2) image density conversion method. However, in the former method, there is a disadvantage in that ups and downs of an image become conspicuous; whereas, in the latter case, there is a disadvantage in that density magnification must be implemented using arithmetic equations, which tend to make an arithmetic circuit complicated in structure.